Under the influence of several autoantibodies (such as Thyroid-stimulating immunoglobulin), the thyroid follicles become hyperplastic. Overcrowding of nuclei causes thyroid epithelium to be thrown into papillary folds as illustrated in this image. They should not be mistaken for papillary thyroid carcinoma. In Graves disease, such changes are focal and lack the nuclear features of papillary carcinoma. In addition, the clinical presentation will usually point to the correct diagnosis.